This invention relates to apparatus for treating a sheet material with radiation which is particularly, although not exclusively, suitable for drying printing ink, varnishes or other similar coatings, or for curing such coatings.
Radiant lamps have become increasingly widely used in the printing industry for drying or curing inks or varnishes on sheet material. Such sheet material is frequently drawn by a tubular gripper mechanism, one sheet at a time, beneath an ultra-violet lamp. The usual relationship between the gripper mechanism and the shape and position of the reflector used in the lamp has resulted in a shadow of the gripper mechanism being cast at the edge of the sheet material. Thus ink or varnish in this region will either not be dried or cured or will only be partially dried or cured.
One solution to this problem has been to leave the leading edge of each sheet blank. This has resulted in wastage and makes the printing process more expensive.